Just wanted to say that kudos for making the effort to take your puppy out and about even though it is hard for you. I can relate since I live out in the boonies, half an hour from town, in Northern BC where the winters days are very, very short, and the temps can be brutal. I have Asperger's syndrome, so not really social and outgoing, and tend to want to isolate myself, but like you, made the effort early on with both my rescue, then my new dog, to take them out and give them as many new experiences as I could think of.
You can walk your pup around malls, construction sites, down busy streets. For me, just driving out to a residential area and having leash walks around cars, city buses, other people walking their dogs, etc, was something new and different. I've taken my guys to a local ski hill to watch the skiers zoom down the hills (and getting lots of attention and petting too!), walked in a hockey arena to watch hockey practice (be aware that this is LOUD!!), regular outings to a horse club to walk around the paddocks and be exposed to horses, etc.
Lots and lots of ideas here:
And as Elaine has said, your pup does not need to get petted by everyone, just going out and about what I refer to as "the real word" has a lot of benefits.